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1. Unified Platform for Automated Tests of Inverter-Based Resources with Harware-in-the-loop

Author

Luiz F. R. Menegazzo, Anderson L. N. Severo, Lucas Bisêlo Piton, Catherine Marquioro de Freitas, Ricardo Jochann Franceschi Bortolini, Lucas Vizzotto Bellinaso, Leandro Michels, and Fernanda de Morais Carnielutti

Subjects
CHIL, Inverter-based Resources, Hardware-in-the-loop, Photovoltaic Inverter, Test automation, Test Platform, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Testing of inverter-based resources (IBRs) faces challenges in establishing standardized procedures across all product development stages. Most of the testing approaches use Hardware-in-the-Loop (HIL) during the early stages independently from the final product testing, which can lead to discrepant results. To solve these issues, this paper proposes a unified platform for automatically testing IBRs. It can be used during all product development stages, from pure simulation to Controller Hardware-in-the-Loop (CHIL) and finally on the complete commercial product, ensuring uniform test procedures with different test setups. A case study describing compliance tests of grid-connection codes of photovoltaic (PV) inverters are presented to demonstrate the proposed approach. Experimental tests were performed in accordance to Brazilian grid-connection codes in an ISO/IEC 17025 accredited laboratory. The results obtained with the proposed platform in CHIL and full-hardware showed high similarity with the ones obtained with the accredited laboratory, validating the proposed approach. In addition, the platform can be used to perform tests not specified in standards and to verify the performance of IBRs in operating conditions that are often difficult to be tested in laboratory. Ensuring consistent test procedures, the platform facilitates comparable results along all the testing stages, reducing the product development cycle.

Published
2024
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2. Search for the γ decay of the narrow near-threshold proton resonance in 11B

Author

S. Bottoni, G. Corbari, S. Leoni, B. Fornal, A. Goasduff, S. Capra, D. Mengoni, E. Albanese, S. Ziliani, G. Benzoni, A.M. Sánchez-Benítez, A. Bracco, D. Brugnara, F. Camera, M. Ciemała, N. Cieplicka-Oryńczak, F.C.L. Crespi, J.A. Dueñas, A. Gadea, F. Galtarossa, E. Gamba, A. Gottardo, A. Gozzelino, J. Ha, Ł.W. Iskra, T. Marchi, R. Menegazzo, B. Million, D.R. Napoli, G. Pasqualato, J. Pellumaj, R.M. Pérez-Vidal, S. Pigliapoco, M. Polettini, C. Porzio, F. Recchia, K. Rezynkina, J.J. Valiente-Dóbon, O. Wieland, I. Zanon, and G. Zhang

Subjects
11B, Near-threshold resonance, γ-ray decay, Continuum shell model, Physics, QC1-999
Abstract

The γ decay of the elusive narrow, near-threshold proton resonance in 11B was investigated at Laboratori Nazionali di Legnaro (INFN) in a particle-γ coincidence experiment, using the 6Li(6Li,pγ) fusion-evaporation reaction and the GALILEO-GALTRACE setup. No clear signature was found for a possible E1 decay to the 1/21−, first-excited state of 11B, predicted by the Shell Model Embedded in the Continuum (SMEC) with a branching of 0.98−69+167×10−3 with respect to the dominant particle-decaying modes. The statistical analysis of the γ-ray spectrum provided an average upper limit of 2.37×10−3 for this γ-ray branching, with a global significance of 5σ. On the other hand, by imposing a global confidence level of 3σ, a significant excess of counts was observed for E=γ9300(20) keV, corresponding to a resonance energy of 11429(20) keV (namely 200(20) keV above the proton separation energy of 11B) and a γ-ray branching of 1.12(35)×10−3. This result is compatible with the SMEC calculations, potentially supporting the existence of a near-threshold proton resonance in 11B.

Published
2024
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3. An alternative viewpoint on the nuclear structure towards 100Sn: Lifetime measurements in 105Sn

Author

G. Pasqualato, A. Gottardo, D. Mengoni, A. Goasduff, J.J. Valiente-Dobón, F. Nowacki, S. Péru, N. Pillet, G. de Angelis, S.D. Bakes, T. Bayram, D. Bazzacco, G. Benzoni, D. Brugnara, M. Cicerchia, P. Colovic, M.L. Cortés, A. Gadea, F. Galtarossa, M. Górska, A. Gozzelino, E. Gregor, N. Hubbard, A. Illana, M. Jurado, S.M. Lenzi, G. Mantovani, T. Marchi, R. Menegazzo, A. Montaner-Pizá, D.R. Napoli, F. Recchia, M. Siciliano, D. Testov, S. Szilner, and I. Zanon

Subjects
Nuclear structure, γ-ray spectroscopy, Transition probabilities, Neutron-deficient isotopes, Odd-mass nuclei, Lifetime measurements, Physics, QC1-999
Abstract

This work aims at presenting an alternative approach to the long standing problem of the B(E2) values in Sn isotopes in the vicinity of the N=Z double-magic nucleus 100Sn, until now predominantly measured with relativistic and intermediate-energy Coulomb excitation reactions. The direct measurement of the lifetime of low-lying excited states in odd-even Sn isotopes provides a new and precise guidance for the theoretical description of the nuclear structure in this region. Lifetime measurements have been performed in 105Sn for the first time with the coincidence Recoil Distance Doppler Shift technique. The lifetime results for the 7/21+ first excited state and the 11/21+ state, 2+(104Sn) ⊗ν1g7/2 multiplet member, are discussed in comparison with state-of-the-art shell model and mean field calculations, highlighting the crucial contribution of proton excitation across the core of 100Sn. The reduced transition probability B(E2) of the 11/21+ core-coupled state points out an enhanced staggering with respect to the B(E2; 21+→01+) in the even-mass 104Sn and 106Sn isotopes.

Published
2023
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5. High resolution γ-ray spectrometry using GALILEO array

Author

D. .. Testov, J. J. Valiente-Dobon, D. .. Mengoni, F. .. Recchia, A. .. Goasduff, A. .. Boso, S. .. Lenzi, G. .. De Angelis, S. .. Bakes, C. .. Boiano, B. .. Cederwall, G. .. Colucci, M. .. Cicerchia, P. .. Colovic, F. .. Didierjean, M. .. Doncel, J. A. Duenas, F. .. Galtarossa, A. .. Gozzelino, K. .. Hadynska-Klek, R. .. Isocrate, G. .. Jaworski, P. R. John, H. .. Liu, S. .. Lunardi, R. .. Menegazzo, A. .. Mentana, V. .. Modamio, A. .. Nannini, D. R. Napoli, M. .. Palacz, G. .. Pasqualato, M. .. Rocchini, S. .. Riccetto, B. .. Saygi, E. .. Sahin, M. .. Siciliano, Yu. .. Sobolev, and S. .. Szilner

Subjects
γ-ray spectroscopy, γ-ray spectrometer, nuclear structure, nuclearstate lifetime, Physics, QC1-999
Abstract

The GALILEO γ -ray spectrometer has been constructed at the Legnaro National Laboratory of INFN (LNL-INFN). It can be coupled to advanced ancillary devices which allows nuclear structure studies employing the variety of in-beam γ -ray spectroscopy methods. Such studies benefit from reactions induced by the intense stable beams delivered by the Tandem-ALPI-PIAVE accelerator complex and by the radioactive beams which will be provided by the SPES facility. In this paper we outline two experiments performed within the experimental campaign at GALILEO coupled to the EUCLIDES Si-ball and the Neutron Wall array. The first one was aimed at spectroscopic studies in A=31 mirror nuclei and the second one at measurements of lifetimes of excited states in nuclei in the vicinity of 100 Sn.

Published
2021
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6. High-spin states in 212Po above the α-decaying (18+) isomer

Author

L. Zago, A. Gottardo, J.J. Valiente-Dobón, G. Benzoni, A. Gadea, M. Górska, S. Lunardi, Zs. Podolyák, P.H. Regan, D. Rudolph, A. Algora, G. de Angelis, D. Bazzacco, J. Benlliure, P. Boutachkov, A. Bracco, A.M. Bruce, F. Camera, E. Casarejos, M.L. Cortés, F.C.L. Crespi, A. Corsi, C. Domingo-Pardo, M. Doncel, T. Engert, H. Geissel, J. Gerl, A. Goasduff, N. Goel, J. Grebosz, E. Gregor, T. Habermann, S. Klupp, I. Kojouharov, N. Kurz, S.M. Lenzi, S. Leoni, S. Mandal, R. Menegazzo, D. Mengoni, B. Million, A.I. Morales, D.R. Napoli, F. Naqvi, C. Nociforo, M. Pfützner, S. Pietri, A. Prochazka, F. Recchia, E. Sahin, H. Schaffner, A. Sharma, B. Sitar, D. Siwal, P. Strmen, I. Szarka, C.A. Ur, P.M. Walker, H. Weick, O. Wieland, and H.-J. Wollersheim

Subjects
γ spectroscopy, Isomer spectroscopy, High-spin spectroscopy, Physics, QC1-999
Abstract

The nucleus 212Po has been produced through the fragmentation of a 238U primary beam at 1 GeV/nucleon at GSI, separated with the FRagment Separator, FRS, and studied via isomer γ-decay spectroscopy with the RISING setup. Two delayed previously unknown γ rays have been observed. One has been attributed to the E3 decay of a 21− isomeric state feeding the α-emitting 45-s (18+) high-spin isomer. The other γ-ray line has been assigned to the decay of a higher-lying 23+ metastable state. These are the first observations of high-spin states above the 212Po (18+) isomer, by virtue of the selectivity obtained via ion-by-ion identification of 238U fragmentation products. Comparison with shell-model calculations points to shortfalls in the nuclear interactions involving high-j proton and neutron orbitals, to which the region around Z∼100 is sensitive.

Published
2022
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7. A high resolution γ-ray array for the pandora plasma trap

Author

A. Goasduff, D. Santonocito, R. Menegazzo, S. Capra, A. Pullia, W. Raniero, D. Rosso, N. Toniolo, L. Zago, E. Naselli, and D. R. Napoli

Subjects
γ-ray spectroscopy, HPGe detectors, front-end electronics, digital electronics, distributed DAQ, plasma trap, Physics, QC1-999
Abstract

The measurement of β-decay rates in plasma, simulating stellar-like conditions, is of high interest for the investigation of radionuclides involved in nuclear astrophysics processes. In the new PANDORA plasma trap, to be built at the INFN—Laboratori Nazionali del Sud of Catania (Italy), the β-decay rates will be estimated by detecting the γ-rays emitted by the daughter nuclei trapped in the confined plasma. The present work describes the high efficiency High Purity Germanium (HPGe) detector array that will be placed around the magnetic trap for this purpose, as well as the front-end electronics and acquisition system suitable for the array operation in presence of a high counting rate background originating from Bremsstrahlung radiation.

Published
2022
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8. Transition probabilities in 31P and 31S: A test for isospin symmetry

Author

D. Tonev, G. de Angelis, I. Deloncle, N. Goutev, G. De Gregorio, P. Pavlov, I.L. Pantaleev, S. Iliev, M.S. Yavahchova, P.G. Bizzeti, A. Demerdjiev, D.T. Dimitrov, E. Farnea, A. Gadea, E. Geleva, C.Y. He, H. Laftchiev, S.M. Lenzi, S. Lunardi, N. Marginean, R. Menegazzo, D.R. Napoli, F. Nowacki, R. Orlandi, H. Penttilä, F. Recchia, E. Sahin, R.P. Singh, M. Stoyanova, C.A. Ur, and H.-F. Wirth

Subjects
Mirror nuclei, Lifetime measurements, Transition probabilities, Isospin symmetry, Microscopic multiphonon model, Physics, QC1-999
Abstract

Excited states in the mirror nuclei 31P and 31S were populated in the 1p and 1n exit channels of the reaction 20Ne + 12C, at a beam energy of 33 MeV. The 20Ne beam was delivered for the first time by the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Angular correlations of coincident γ-rays and Doppler-shift attenuation lifetime measurements were performed using the multi-detector array GASP in conjunction with the EUCLIDES charged particle detector. In the observed B(E1) strengths, the isoscalar component, amounting to 24% of the isovector one, provides strong evidence for breaking of the isospin symmetry in the A=31 mass region. Self-consistent beyond mean field calculations using Equation of Motion method based on a chiral potential and including two- and three-body forces reproduce well the experimental B(E1) strengths, reinforcing our conclusion. Coherent mixing from higher-lying states involving the Giant Isovector Monopole Resonance accounts well for the effect observed. The breaking of the isospin symmetry originates from the violation of the charge symmetry of the two- and three-body parts of the potential, only related to the Coulomb interaction.

Published
2021
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9. Expanding benefits from cardiac resynchronization therapy to exercise‐induced left bundle branch block in advanced heart failure

Author

Fernando L. Scolari, Anderson D. Silveira, Willian R. Menegazzo, Ana Paula Chedid Mendes, Maurício Pimentel, Nadine Clausell, and Livia A. Goldraich

Subjects
Cardiac resynchronization therapy, Exercise‐induced left bundle branch block, Heart failure, Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Indications of cardiac resynchronization therapy (CRT) do not include exercise‐induced left bundle branch block, but functional impairment could be improved with CRT in such cases. A 57‐year‐old woman with idiopathic dilated cardiomyopathy (ejection fraction 23%) presented with New York Heart Association Class IV and recurrent hospitalizations. During heart transplant evaluation, a new onset of intermittent left bundle branch block was observed on the cardiopulmonary exercise test. CRT was implanted, and 97% resynchronization rate was achieved. In 12 month follow‐up, both clinical and prognostic exercise parameters improved. In patients with heart failure with reduced ejection fraction and no left bundle branch block at rest, exercise test can uncover electromechanical dyssynchrony that may benefit from CRT.

Published
2020
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10. Direct measurements of low-energy resonance strengths of the 23Na(p,γ)24Mg reaction for astrophysics

Author

A. Boeltzig, A. Best, F.R. Pantaleo, G. Imbriani, M. Junker, M. Aliotta, J. Balibrea-Correa, D. Bemmerer, C. Broggini, C.G. Bruno, R. Buompane, A. Caciolli, F. Cavanna, T. Chillery, G.F. Ciani, P. Corvisiero, L. Csedreki, T. Davinson, R.J. deBoer, R. Depalo, A. Di Leva, Z. Elekes, F. Ferraro, E.M. Fiore, A. Formicola, Zs. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, Gy. Gyürky, I. Kochanek, M. Lugaro, P. Marigo, R. Menegazzo, V. Mossa, F. Munnik, V. Paticchio, R. Perrino, D. Piatti, P. Prati, L. Schiavulli, K. Stöckel, O. Straniero, F. Strieder, T. Szücs, M.P. Takács, D. Trezzi, M. Wiescher, and S. Zavatarelli

Subjects
Physics, QC1-999
Abstract

The NeNa and the MgAl cycles play a fundamental role in the nucleosynthesis of asymptotic giant branch stars undergoing hot bottom burning. The Na23(p,γ)24Mg reaction links these two cycles and a precise determination of its rate is required to correctly estimate the contribution of these stars to the chemical evolution of various isotopes of Na, Mg and Al. At temperatures of 50≲T≲110MK, narrow resonances at Ep=140 and 251keV are the main contributors to the reaction rate, in addition to the direct capture that dominates in the lower part of the temperature range. We present new measurements of the strengths of these resonances at the Laboratory for Underground Nuclear Astrophysics (LUNA). We have used two complementary detection approaches: high efficiency with a 4π BGO detector for the 140keV resonance, and high resolution with a HPGe detector for the 251keV resonance. Thanks to the reduced cosmic ray background of LUNA, we were able to determine the resonance strength of the 251keV resonance as ωγ=482(82)μeV and observed new gamma ray transitions for the decay of the corresponding state in Mg24 at Ex=11931keV. With the highly efficient BGO detector, we observed a signal for the 140keV resonance for the first time in a direct measurement, resulting in a strength of ωγ140=1.46−0.53+0.58neV (68% CL). Our measurement reduces the uncertainty of the Na23(p,γ)24Mg reaction rate in the temperature range from 0.05 to 0.1GK to at most −35%+50% at 0.07GK. Accordingly, our results imply a significant reduction of the uncertainties in the nucleosynthesis calculations. Keywords: Experimental nuclear astrophysics, Underground nuclear physics, Hydrogen burning, Stellar evolution

Published
2019
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11. Improved astrophysical rate for the 18O(p,α)15N reaction by underground measurements

Author

C.G. Bruno, M. Aliotta, P. Descouvemont, A. Best, T. Davinson, D. Bemmerer, A. Boeltzig, C. Broggini, A. Caciolli, F. Cavanna, T. Chillery, G.F. Ciani, P. Corvisiero, R. Depalo, A. Di Leva, Z. Elekes, F. Ferraro, A. Formicola, Zs. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, Gy. Gyürky, G. Imbriani, M. Junker, M. Lugaro, P. Marigo, R. Menegazzo, V. Mossa, F.R. Pantaleo, D. Piatti, P. Prati, K. Stöckel, O. Straniero, F. Strieder, T. Szücs, M.P. Takács, and D. Trezzi

Subjects
Physics, QC1-999
Abstract

The 18O(p,α)15N reaction affects the synthesis of 15N, 18O and 19F isotopes, whose abundances can be used to probe the nucleosynthesis and mixing processes occurring deep inside asymptotic giant branch (AGB) stars. We performed a low-background direct measurement of the 18O(p,α)15N reaction cross-section at the Laboratory for Underground Nuclear Astrophysics (LUNA) from center of mass energy Ec.m.=340 keV down to Ec.m.=55 keV, the lowest energy measured to date corresponding to a cross-section of less than 1 picobarn/sr. The strength of a key resonance at center of mass energy Er=90 keV was found to be a factor of 10 higher than previously reported. A multi-channel R-matrix analysis of our and other data available in the literature was performed. Over a wide temperature range, T=0.01–1.00 GK, our new astrophysical rate is both more accurate and precise than recent evaluations. Stronger constraints can now be placed on the physical processes controlling nucleosynthesis in AGB stars with interesting consequences on the abundance of 18O in these stars and in stardust grains, specifically on the production sites of oxygen-rich Group II grains. Keywords: Stellar hydrogen burning, Hydrostatic stellar nucleosynthesis

Published
2019
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12. Manifestation of the Berry phase in the atomic nucleus 213Pb

Author

J.J. Valiente-Dobón, A. Gottardo, G. Benzoni, A. Gadea, S. Lunardi, A. Algora, G. de Angelis, D. Bazzacco, J. Benlliure, P. Boutachkov, A. Bracco, A.M. Bruce, F. Camera, E. Casarejos, M.L. Cortés, F.C.L. Crespi, A. Corsi, C. Domingo-Pardo, M. Doncel, T. Engert, H. Geissel, J. Gerl, A. Goasduff, N. Goel, M. Górska, J. Grebosz, E. Gregor, T. Habermann, S. Klupp, I. Kojouharov, N. Kurz, S.M. Lenzi, S. Leoni, S. Mandal, R. Menegazzo, D. Mengoni, B. Million, A.I. Morales, D.R. Napoli, F. Naqvi, C. Nociforo, M. Pfützner, S. Pietri, Zs. Podolyák, A. Prochazka, F. Recchia, P.H. Regan, D. Rudolph, E. Sahin, H. Schaffner, A. Sharma, B. Sitar, D. Siwal, P. Strmen, I. Szarka, C.A. Ur, P.M. Walker, H. Weick, O. Wieland, H.-J. Wollersheim, and P. Van Isacker

Subjects
Physics, QC1-999
Abstract

The neutron-rich 213Pb isotope was produced in the fragmentation of a primary 1 GeV A 238U beam, separated in FRS in mass and atomic number, and then implanted for isomer decay γ-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in 213Pb are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum J=0. The conservation of seniority is a consequence of a geometric phase associated with particle-hole conjugation, which becomes observable in semi-magic nuclei where nucleons half-fill the valence shell. The γ-ray spectroscopic observables in 213Pb are thus found to be driven by two mechanisms, particle-hole conjugation and seniority conservation, which are intertwined through a Berry phase.

Published
2021
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13. Low-lying electric dipole γ-continuum for the unstable 62,64Fe nuclei: Strength evolution with neutron number

Author

R. Avigo, O. Wieland, A. Bracco, F. Camera, F. Ameil, T. Arici, A. Ataç, D. Barrientos, D. Bazzacco, P. Bednarczyk, G. Benzoni, B. Birkenbach, N. Blasi, H.C. Boston, S. Bottoni, S. Brambilla, B. Bruyneel, M. Ciemała, E. Clément, M.L. Cortés, F.C.L. Crespi, D.M. Cullen, D. Curien, F. Didierjean, C. Domingo-Pardo, G. Duchêne, J. Eberth, A. Görgen, A. Gadea, J. Gerl, N. Goel, P. Golubev, V. González, M. Górska, A. Gottardo, E. Gregor, G. Guastalla, T. Habermann, L.J. Harkness-Brennan, A. Jungclaus, M. Kmiecik, I. Kojouharov, W. Korten, N. Kurz, M. Labiche, N. Lalović, S. Leoni, M. Lettmann, A. Maj, R. Menegazzo, D. Mengoni, E. Merchan, B. Million, A.I. Morales, D.R. Napoli, C. Nociforo, J. Nyberg, N. Pietralla, S. Pietri, Zs. Podolyák, V.Yu. Ponomarev, A. Pullia, B. Quintana, G. Rainovski, D. Ralet, F. Recchia, M. Reese, P. Regan, P. Reiter, S. Riboldi, D. Rudolph, M.D. Salsac, E. Sanchis, L.G. Sarmiento, H. Schaffner, J. Simpson, O. Stezowski, J.J. Valiente-Dobón, and H.J. Wollersheim

Subjects
64Fe, 62Fe, Nuclear structure, Dipole excitation around neutron threshold, Physics, QC1-999
Abstract

The γ-ray emission from the nuclei 62,64Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei 62,64Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1− states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy.

Published
2020
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14. Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn

Author

M. Siciliano, J.J. Valiente-Dobón, A. Goasduff, F. Nowacki, A.P. Zuker, D. Bazzacco, A. Lopez-Martens, E. Clément, G. Benzoni, T. Braunroth, F.C.L. Crespi, N. Cieplicka-Oryńczak, M. Doncel, S. Ertürk, G. de France, C. Fransen, A. Gadea, G. Georgiev, A. Goldkuhle, U. Jakobsson, G. Jaworski, P.R. John, I. Kuti, A. Lemasson, T. Marchi, D. Mengoni, C. Michelagnoli, T. Mijatović, C. Müller-Gatermann, D.R. Napoli, J. Nyberg, M. Palacz, R.M. Pérez-Vidal, B. Sayği, D. Sohler, S. Szilner, D. Testov, M. Zielińska, D. Barrientos, B. Birkenbach, H.C. Boston, A.J. Boston, B. Cederwall, J. Collado, D.M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Dudouet, J. Eberth, F.J. Egea-Canet, V. González, L.J. Harkness-Brennan, H. Hess, D.S. Judson, A. Jungclaus, W. Korten, M. Labiche, A. Lefevre, S. Leoni, H. Li, A. Maj, R. Menegazzo, B. Million, A. Pullia, F. Recchia, P. Reiter, M.D. Salsac, E. Sanchis, O. Stezowski, and Ch. Theisen

Subjects
Lifetime, Nuclear structure, Multi-nucleon transfer, Light Sn, Tracking array, Physics, QC1-999
Abstract

The lifetimes of the low-lying excited states 2+ and 4+ have been directly measured in the neutron-deficient 106,108Sn isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted γ rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2;21+→0g.s.+) values and it describes well the experimental pattern for 104−114Sn; the B(E2;41+→21+) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in 108Sn.

Published
2020
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15. Search for time modulations in the decay constant of 40K and 226Ra at the underground Gran Sasso Laboratory

Author

E. Bellotti, C. Broggini, G. Di Carlo, M. Laubenstein, and R. Menegazzo

Subjects
Physics, QC1-999
Abstract

Time modulations at per mil level have been reported to take place in the decay constant of several nuclei with period of one year (most cases) but also of about one month or one day. On the other hand, experiments with similar or better sensitivity have been unable to detect any modulation. In this letter we give the results of the activity study of two different sources: 40K and 226Ra. The two gamma spectrometry experiments have been performed underground at the Gran Sasso Laboratory, this way suppressing the time dependent cosmic ray background. Briefly, our measurements reached the sensitivity of 3.4 and 3.5 parts over 106 for 40K and 226Ra, respectively (1 sigma) and they do not show any statistically significant evidence of time dependence in the decay constant. We also give the results of the activity measurement at the time of the two strong X-class solar flares which took place in September 2017. Our data do not show any unexpected time dependence in the decay rate of 40K in correspondence with the two flares. To the best of our knowledge, these are the most precise and accurate results on the stability of the decay constant as function of time. Keywords: Radioactivity, Annual modulation, Solar flare, Gran Sasso

Published
2018
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16. Cross section of the reaction 18O(p,γ)19F at astrophysical energies: The 90 keV resonance and the direct capture component

Author

A. Best, F.R. Pantaleo, A. Boeltzig, G. Imbriani, M. Aliotta, J. Balibrea-Correa, D. Bemmerer, C. Broggini, C.G. Bruno, R. Buompane, A. Caciolli, F. Cavanna, T. Chillery, G.F. Ciani, P. Corvisiero, L. Csedreki, T. Davinson, R.J. deBoer, R. Depalo, A. Di Leva, Z. Elekes, F. Ferraro, E.M. Fiore, A. Formicola, Zs. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, Gy. Gyürky, M. Junker, I. Kochanek, M. Lugaro, P. Marigo, R. Menegazzo, V. Mossa, V. Paticchio, R. Perrino, D. Piatti, P. Prati, L. Schiavulli, K. Stöckel, O. Straniero, F. Strieder, T. Szücs, M.P. Takács, D. Trezzi, M. Wiescher, and S. Zavatarelli

Subjects
Physics, QC1-999
Abstract

The observation of oxygen isotopes in giant stars sheds light on mixing processes operating in their interiors. Due to the very strong correlation between nuclear burning and mixing processes it is very important to reduce the uncertainty on the cross sections of the nuclear reactions that are involved. In this paper we focus our attention on the reaction O18(p,γ)19F. While the O18(p,α)15N channel is thought to be dominant, the (p,γ) channel can still be an important component in stellar burning in giants, depending on the low energy cross section. So far only extrapolations from higher-energy measurements exist and recent estimates vary by orders of magnitude. These large uncertainties call for an experimental reinvestigation of this reaction. We present a direct measurement of the O18(p,γ)19F cross section using a high-efficiency 4π BGO summing detector at the Laboratory for Underground Nuclear Astrophysics (LUNA). The reaction cross section has been directly determined for the first time from 140 keV down to 85 keV and the different cross section components have been obtained individually. The previously highly uncertain strength of the 90 keV resonance was found to be 0.53 ± 0.07 neV, three orders of magnitude lower than an indirect estimate based on nuclear properties of the resonant state and a factor of 20 lower than a recently established upper limit, excluding the possibility that the 90 keV resonance can contribute significantly to the stellar reaction rate. Keywords: Experimental nuclear astrophysics, Underground nuclear physics, Hydrogen burning, Stellar evolution

Published
2019
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17. Evidence of octupole-phonons at high spin in 207Pb

Author

D. Ralet, E. Clément, G. Georgiev, A.E. Stuchbery, M. Rejmund, P. Van Isacker, G. de France, A. Lemasson, J. Ljungvall, C. Michelagnoli, A. Navin, D.L. Balabanski, L. Atanasova, A. Blazhev, G. Bocchi, R. Carroll, J. Dudouet, E. Dupont, B. Fornal, S. Franchoo, C. Fransen, C. Müller-Gatermann, A. Goasduff, A. Gadea, P.R. John, D. Kocheva, T. Konstantinopoulos, A. Korichi, A. Kusoglu, S.M. Lenzi, S. Leoni, R. Lozeva, A. Maj, R. Perez, N. Pietralla, C. Shand, O. Stezowski, D. Wilmsen, D. Yordanov, D. Barrientos, P. Bednarczyk, B. Birkenbach, A.J. Boston, H.C. Boston, I. Burrows, B. Cederwall, M. Ciemala, J. Collado, F. Crespi, D. Cullen, H.J. Eberth, J. Goupil, L. Harkness, H. Hess, A. Jungclaus, W. Korten, M. Labiche, R. Menegazzo, D. Mengoni, B. Million, J. Nyberg, Zs. Podolyák, A. Pullia, B. Quintana Arnés, F. Recchia, P. Reiter, F. Saillant, M.D. Salsac, E. Sanchis, C. Theisen, J.J. Valiente Dobon, and O. Wieland

Subjects
Physics, QC1-999
Abstract

A lifetime measurement of the 19/2− state in 207Pb has been performed using the Recoil Distance Doppler-Shift (RDDS) method. The nuclei of interest were produced in multi-nucleon transfer reactions induced by a 208Pb beam impinging on a 100Mo enriched target. The beam-like nuclei were detected and identified in terms of their atomic mass number in the VAMOS++ spectrometer while the prompt γ rays were detected by the AGATA tracking array. The measured large reduced transition probability B(E3,19/2−→13/2+)=40(8) W.u. is the first indication of the octupole phonon at high spin in 207Pb. An analysis in terms of a particle-octupole-vibration coupling model indicates that the measured B(E3) value in 207Pb is compatible with the contributions from single-phonon and single particle E3 as well as E3 strength arising from the double-octupole-phonon 6+ state, all adding coherently. A crucial aspect of the coupling model, namely the strong mixing between single-hole and the phonon-hole states, is confirmed in a realistic shell-model calculation. Keywords: AGATA spectrometer, γ-Ray tracking, VAMOS++ spectrometer, Plunger device, Nuclear deformation, Octupole phonon

Published
2019
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18. Isospin dependence of electromagnetic transition strengths among an isobaric triplet

Author

A. Boso, S.A. Milne, M.A. Bentley, F. Recchia, S.M. Lenzi, D. Rudolph, M. Labiche, X. Pereira-Lopez, S. Afara, F. Ameil, T. Arici, S. Aydin, M. Axiotis, D. Barrientos, G. Benzoni, B. Birkenbach, A.J. Boston, H.C. Boston, P. Boutachkov, A. Bracco, A.M. Bruce, B. Bruyneel, B. Cederwall, E. Clement, M.L. Cortes, D.M. Cullen, P. Désesquelles, Zs. Dombràdi, C. Domingo-Pardo, J. Eberth, C. Fahlander, M. Gelain, V. González, P.R. John, J. Gerl, P. Golubev, M. Górska, A. Gottardo, T. Grahn, L. Grassi, T. Habermann, L.J. Harkness-Brennan, T.W. Henry, H. Hess, I. Kojouharov, W. Korten, N. Lalović, M. Lettmann, C. Lizarazo, C. Louchart-Henning, R. Menegazzo, D. Mengoni, E. Merchan, C. Michelagnoli, B. Million, V. Modamio, T. Moeller, D.R. Napoli, J. Nyberg, B.S. Nara Singh, H. Pai, N. Pietralla, S. Pietri, Zs. Podolyak, R.M. Perez Vidal, A. Pullia, D. Ralet, G. Rainovski, M. Reese, P. Reiter, M.D. Salsac, E. Sanchis, L.G. Sarmiento, H. Schaffner, L.M. Scruton, P.P. Singh, C. Stahl, S. Uthayakumaar, J.J. Valiente-Dobón, and O. Wieland

Subjects
Physics, QC1-999
Abstract

Electric quadrupole matrix elements, Mp, for the Jπ=2+→0+, ΔT=0, T=1 transitions across the A=46 isobaric multiplet 46Cr-46V-46Ti have been measured at GSI with the FRS-LYCCA-AGATA setup. This allows direct insight into the isospin purity of the states of interest by testing the linearity of Mp with respect to Tz. Pairs of nuclei in the T=1 triplet were studied using identical reaction mechanisms in order to control systematic errors. The Mp values were obtained with two different methodologies: (i) a relativistic Coulomb excitation experiment was performed for 46Cr and 46Ti; (ii) a “stretched target” technique was adopted here, for the first time, for lifetime measurements in 46V and 46Ti. A constant value of Mp across the triplet has been observed. Shell-model calculations performed within the fp shell fail to reproduce this unexpected trend, pointing towards the need of a wider valence space. This result is confirmed by the good agreement with experimental data achieved with an interaction which allows excitations from the underlying sd shell. A test of the linearity rule for all published data on complete T=1 isospin triplets is presented.

Published
2019
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20. Spectroscopic quadrupole moments in Xe124

Author

E. Clément, A. Lemasson, M. Rejmund, B. Jacquot, D. Ralet, C. Michelagnoli, D. Barrientos, P. Bednarczyk, G. Benzoni, A. J. Boston, A. Bracco, B. Cederwall, M. Ciemala, J. Collado, F. Crespi, C. Domingo-Pardo, J. Dudouet, H. J. Eberth, G. de France, A. Gadea, V. Gonzalez, A. Gottardo, L. Harkness, H. Hess, A. Jungclaus, A. Kaşkaş, W. Korten, S. M. Lenzi, S. Leoni, J. Ljungvall, R. Menegazzo, D. Mengoni, B. Million, D. R. Napoli, J. Nyberg, Zs. Podolyak, A. Pullia, B. Quintana Arnés, F. Recchia, N. Redon, P. Reiter, M. D.Salsac, E. Sanchis, M. Şenyiğit, M. Siciliano, D. Sohler, O. Stezowski, C. Theisen, J. J. Valiente Dobón, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Science and Technology Facilities Council (UK), Agence Nationale de la Recherche (France), Department of Energy (US), Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, and Clément, E.

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

9 pags., 8 figs., 4 tabs., Background: The Xe isotopic chain with four valence protons above the Z=50 shell closure is an ideal laboratory for the study of the evolution of nuclear deformation. At the N=82 shell closure, Xe136 presents all characteristics of a doubly closed shell nucleus with a spherical shape. In the very neutron-deficient isotopes close to N=50, the α-decay chain of Xe was investigated to probe the radioactive decay properties near the drip-line and the magicity of Sn100. Additionally, the Xe isotopes present higher order symmetries in the nuclear deformation such as the octupole degree of freedom near N=60 and N=90 or O(6) symmetry in stable isotopes. Purpose: The relevance of the O(6) symmetry has been investigated by measuring the spectroscopic quadrupole moment of the first excited states in Xe124. In the O(6) symmetry limit, the spectroscopic quadrupole moment of collective states is expected to be null. Method: A stable Xe124 beam with energies of 4.03A MeV and 4.11A MeV was used to bombard a natW target at the GANIL facility. Excited states were populated via the safe Coulomb excitation reaction. The collision of the heavy ions with a large Z at low energy make this reaction sensitive to the diagonal E2 matrix element of the excited states. The recoils were detected in the VAMOS++ magnetic spectrometer and the γ rays in the AGATA tracking array. The least squares fitting code gosia was used for the analysis to extract both E2 and M1 transitional and E2 diagonal matrix elements. Results: The rotational ground state band was populated up to the 81+ state as well as the 22+ and 42+ states. Using high precision spectroscopic data to constrain the gosia fit, the spectroscopic quadrupole moments of the 21+, 41+, and 61+ states were determined for the first time. Conclusions: The spectroscopic quadrupole moments were found to be negative, large, and constant in the ground state band underlining the prolate axially deformed ground state band of Xe124. The present experimental data confirm that the O(6) symmetry is substantially broken in Xe124., This work was supported by STFC(UK). This research was also supported by the OASIS Project No. ANR-17-CE31-0026, by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357, by the European Regional Development Fund with Contract No. GINOP-2.3.3-15-2016-00034 and by the Spanish Ministerio de Ciencia e Innovacion under contract PID2020-118265GB-C41. Work partially supported by Grants FPA2017-84756-C4, PID2020- 118265GB-C4 by MCIN/ AEI /10.13039/501100011033, PROMETEO/2019/005 by Generalitat Valenciana and by the FEDER EU funds.

Published
2023
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21. Conceptual design of the AGATA 2π array at LNL

Author

J.J. Valiente-Dobón, R. Menegazzo, A. Goasduff, D. Agguiaro, P. Aguilera, F. Angelini, M. Balogh, D. Bazzacco, J. Benito, G. Benzoni, N. Bez, M. Bolognesi, S. Bottoni, D. Brugnara, S. Carollo, P. Cocconi, A. Cogo, J. Collado, F.C.L. Crespi, A. Ertoprak, R. Escudeiro, F. Galtarossa, E.R. Gamba, A. Gambalonga, B. Góngora Servín, A. Gottardo, A. Gozzelino, M. Gulmini, Z. Huang, T. Marchi, D. Mengoni, P. Modanese, D.R. Napoli, J. Pellumaj, R.M. Pérez-Vidal, S. Pigliapoco, E. Pilotto, L. Ramina, M. Rampazzo, W. Raniero, M. Rebeschini, K. Rezynkina, D. Rosso, M. Scarcioffolo, D. Scarpa, M. Sedlák, R. Smith, N. Toniolo, F. Veronese, V. Volpe, L. Zago, I. Zanon, G. Zhang, R. Abels, M.L. Allegrini, C. Aufranc, G. Baulieu, C. Belkhiria, M. Benettoni, D. Benini, M. Bentley, M. Biasotto, M. Blaizot, J. Blasco Miquel, C. Boiano, A. Boston, H. Boston, A. Boujrad, P. Bourgault, A. Bracco, S. Brambilla, I. Burrows, F. Camera, S. Capra, A. Capsoni, R. Cash, J.V. Civera, E. Clément, S. Coelli, M. Cordwell, L. Corradi, S. Coudert, G. De Angelis, L. De Ruvo, G. Debras, M. Del Fabbro, J. Diklić, N. Dosme, G. Duchene, B. Duclos, J. Dudouet, J. Eberth, S. Elloumi, C. Everett, S. Fantinel, M. Fillinger, E. Fioretto, C. Fransen, A. Gadea, L. Gibelin, V. González, J. Goupil, C. Görgen, A. Grant, K. Green, J. Ha, T. Hartnett, K. Henseler, H. Hess, R. Hirsch, C. Houarner, J. Jacob, T. Joannem, D.S. Judson, N. Karkour, M. Karolak, M. Kebbiri, J. Kieffer, M. Labiche, X. Lafay, P. Le Jeannic, A. Lefevre, E. Legay, F. Legruel, S. Lenzi, S. Leoni, D. Linget, M. Liptrot, A. López-Martens, A. Lotodé, L. Manara, L. Ménager, T. Mijatović, B. Million, A. Minarello, G. Montagnoli, P. Morrall, I. Mullacrane, J. Nyberg, G. Philippon, M. Polettini, F. Popieul, A. Pullia, F. Recchia, P. Reiter, G. Richardt, M. Rocchini, A. Roger, F. Saillant, E. Sanchis, Md.S.R. Laskar, G. Secci, M.-H. Sigward, J. Simpson, N. Solenne, F. Spee, A.M. Stefanini, O. Stézowski, S. Szilner, N. Templeton, Ch. Theisen, S. Thiel, F. Tomasi, S. Tzvetkov, D. Vigano, E. Viscione, O. Wieland, K. Wimmer, G. Wittwer, M. Zielińska, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
AGATA spectrometer, DANTE detector, EUCLIDES detector, LNL facility, Plunger device, PRISMA spectrometer, Pulse shape analysis, TRACE detector, γ-ray tracking, Nuclear and High Energy Physics, Settore FIS/04 - Fisica Nucleare e Subnucleare, ray tracking, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Instrumentation
Abstract

International audience; The Advanced GAmma Tracking Array (AGATA) has been installed at Laboratori Nazionali di Legnaro (LNL), Italy. In this installation, AGATA will consist, at the beginning, of 13 AGATA triple clusters (ATCs) with an angular coverage of 1π, and progressively the number of ATCs will increase up to a 2π angular coverage. This setup will exploit both stable and radioactive ion beams delivered by the Tandem–PIAVE-ALPI accelerator complex and the SPES facility. The new implementation of AGATA at LNL will be used in two different configurations, firstly one coupled to the PRISMA large-acceptance magnetic spectrometer and lately a second one at Zero Degrees, along the beam line. These two configurations will allow us to cover a broad physics program, using different reaction mechanisms, such as Coulomb excitation, fusion-evaporation, transfer and fission at energies close to the Coulomb barrier. These setups have been designed to be coupled with a large variety of complementary detectors such as charged particle detectors, neutron detectors, heavy-ion detectors, high-energy γ-ray arrays, cryogenic and gasjet targets and the plunger device for lifetime measurements. We present in this paper the conceptual design, characteristics and performance figures of this implementation of AGATA at LNL.

Published
2023
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22. Advances in radiative capture studies at LUNA with a segmented BGO detector

Author

J Skowronski, R M Gesuè, A Boeltzig, G F Ciani, D Piatti, D Rapagnani, M Aliotta, C Ananna, F Barile, D Bemmerer, A Best, C Broggini, C G Bruno, A Caciolli, M Campostrini, F Cavanna, P Colombetti, A Compagnucci, P Corvisiero, L Csedreki, T Davinson, R Depalo, A Di Leva, Z Elekes, F Ferraro, A Formicola, Zs Fülöp, G Gervino, A Guglielmetti, C Gustavino, Gy Gyürky, G Imbriani, M Junker, M Lugaro, P Marigo, E Masha, R Menegazzo, V Paticchio, R Perrino, P Prati, V Rigato, L Schiavulli, R S Sidhu, O Straniero, T Szücs, and S Zavatarelli

Subjects
Nuclear and High Energy Physics, gamma-ray total absorption spectroscopy, radiation shielding and background reduction, nuclear astrophysics experiment, activation measurement, segmented bismuth germanium oxide (BGO) detector, Settore FIS/04 - Fisica Nucleare e Subnucleare
Abstract

Studies of charged-particle reactions for low-energy nuclear astrophysics require high sensitivity, which can be achieved by means of detection setups with high efficiency and low backgrounds, to obtain precise measurements in the energy region of interest for stellar scenarios. High-efficiency total absorption spectroscopy is an established and powerful tool for studying radiative capture reactions, particularly if combined with the cosmic background reduction by several orders of magnitude obtained at the Laboratory for Underground Nuclear Astrophysics (LUNA). We present recent improvements in the detection setup with the Bismuth Germanium Oxide (BGO) detector at LUNA, aiming to reduce high-energy backgrounds and increase the summing detection efficiency. The new design results in enhanced sensitivity of the BGO setup, as we demonstrate and discuss in the context of the first direct measurement of the 65 keV resonance (E x = 5672 keV) of the 17O(p,γ)18F reaction. Moreover, we show two applications of the BGO detector, which exploit its segmentation. In the case of complex γ-ray cascades, e.g. the de-excitation of E x = 5672 keV in 18F, the BGO segmentation allows to identify and suppress the beam-induced background signals that mimic the sum peak of interest. We demonstrate another new application for such a detector in form of in situ activation measurements of a reaction with β + unstable product nuclei, e.g. the 14N(p,γ)15O reaction.

Published
2023
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23. Precise measurement of the 222Rn half-life: A probe to monitor the stability of radioactivity

Author

E. Bellotti, C. Broggini, G. Di Carlo, M. Laubenstein, and R. Menegazzo

Subjects
Physics, QC1-999
Abstract

We give the results of a study on the 222Rn decay we performed in the Gran Sasso Laboratory (LNGS) by detecting the gamma rays from the radon progeny. The motivation was to monitor the stability of radioactivity measuring several times per year the half-life of a short lifetime (days) source instead of measuring over a long period the activity of a long lifetime (tens or hundreds of years) source. In particular, we give a possible reason of the large periodical fluctuations in the count rate of the gamma rays due to radon inside a closed canister which has been described in literature and which has been attributed to a possible influence of a component in the solar irradiation affecting the nuclear decay rates. We then provide the result of four half-life measurements we performed underground at LNGS in the period from May 2014 to January 2015 with radon diffused into olive oil. Briefly, we did not measure any change of the 222Rn half-life with a 8⋅10−5 precision. Finally, we provide the most precise value for the 222Rn half-life: 3.82146(16)stat(4)syst days. Keywords: Radioactivity, Radon, Gran Sasso

Published
2015
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24. Level scheme study of Mo92 : Searching for evidence of core excitation

Author

Z. Huang, G. X. Zhang, G. L. Zhang, S. P. Hu, S. M. Lenzi, D. Mengoni, J. L. Ferreira, Y. F. Lv, J. B. Lu, B. Paes, E. N. Cardozo, H. Q. Zhang, H. B. Sun, J. J. Valiente-Dobón, D. Testov, A. Goasduff, D. Bazzacco, P. R. John, D. R. Napoli, F. Galtarossa, F. Recchia, G. de. Angelis, M. Siciliano, R. Menegazzo, and J. Lubian

Published
2022
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25. Evidence of Partial Seniority Conservation in the πg_{9/2} Shell for the N=50 Isotones

Author

R M, Pérez-Vidal, A, Gadea, C, Domingo-Pardo, A, Gargano, J J, Valiente-Dobón, E, Clément, A, Lemasson, L, Coraggio, M, Siciliano, S, Szilner, M, Bast, T, Braunroth, J, Collado, A, Corina, A, Dewald, M, Doncel, J, Dudouet, G, de France, C, Fransen, V, González, T, Hüyük, B, Jacquot, P R, John, A, Jungclaus, Y H, Kim, A, Korichi, M, Labiche, S, Lenzi, H, Li, J, Ljungvall, A, López-Martens, D, Mengoni, C, Michelagnoli, C, Müller-Gatermann, D R, Napoli, A, Navin, B, Quintana, D, Ramos, M, Rejmund, E, Sanchis, J, Simpson, O, Stezowski, D, Wilmsen, M, Zielińska, A J, Boston, D, Barrientos, P, Bednarczyk, G, Benzoni, B, Birkenbach, H C, Boston, A, Bracco, B, Cederwall, D M, Cullen, F, Didierjean, J, Eberth, A, Gottardo, J, Goupil, L J, Harkness-Brennan, H, Hess, D S, Judson, A, Kaşkaş, W, Korten, S, Leoni, R, Menegazzo, B, Million, J, Nyberg, Zs, Podolyak, A, Pullia, D, Ralet, F, Recchia, P, Reiter, K, Rezynkina, M D, Salsac, M, Şenyiğit, D, Sohler, Ch, Theisen, D, Verney, Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, European Commission, Department of Energy (US), Croatian Science Foundation, and Pérez-Vidal, R.M.

Abstract

7 pags., 3 figs., 1 tab., The reduced transition probabilities for the 4_{1}^{+}→2_{1}^{+} and 2_{1}^{+}→0_{1}^{+} transitions in ^{92}Mo and ^{94}Ru and for the 4_{1}^{+}→2_{1}^{+} and 6_{1}^{+}→4_{1}^{+} transitions in ^{90}Zr have been determined in this experiment making use of a multinucleon transfer reaction. These results have been interpreted on the basis of realistic shell-model calculations in the f_{5/2}, p_{3/2}, p_{1/2}, and g_{9/2} proton valence space. Only the combination of extensive lifetime information and large scale shell-model calculations allowed the extent of the seniority conservation in the N=50 g_{9/2} orbital to be understood. The conclusion is that seniority is largely conserved in the first πg_{9/2} orbital., This work was partially supported by MCIN/AEI/10.13039/501100011033 and Generalitat Valenciana, Spain, under Grants No. FPA2017-84756-C4, No. PID2020–118265GB-C4, and No. PROMETEO 2019/005, by the EU FEDER funds, by the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. n654002, by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, by STFC(UK) and by the Croatian Science Foundation under Projects No. 7194 and No. IP-2018-01-1257.

Published
2022

26. Evidence of Partial Seniority Conservation in the πg9/2 Shell for the N=50 Isotones

Author

R. M. Pérez-Vidal, A. Gadea, C. Domingo-Pardo, A. Gargano, J. J. Valiente-Dobón, E. Clément, A. Lemasson, L. Coraggio, M. Siciliano, S. Szilner, M. Bast, T. Braunroth, J. Collado, A. Corina, A. Dewald, M. Doncel, J. Dudouet, G. de France, C. Fransen, V. González, T. Hüyük, B. Jacquot, P. R. John, A. Jungclaus, Y. H. Kim, A. Korichi, M. Labiche, S. Lenzi, H. Li, J. Ljungvall, A. López-Martens, D. Mengoni, C. Michelagnoli, C. Müller-Gatermann, D. R. Napoli, A. Navin, B. Quintana, D. Ramos, M. Rejmund, E. Sanchis, J. Simpson, O. Stezowski, D. Wilmsen, M. Zielińska, A. J. Boston, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, H. C. Boston, A. Bracco, B. Cederwall, D. M. Cullen, F. Didierjean, J. Eberth, A. Gottardo, J. Goupil, L. J. Harkness-Brennan, H. Hess, D. S. Judson, A. Kaşkaş, W. Korten, S. Leoni, R. Menegazzo, B. Million, J. Nyberg, Zs. Podolyak, A. Pullia, D. Ralet, F. Recchia, P. Reiter, K. Rezynkina, M. D. Salsac, M. Şenyiğit, D. Sohler, Ch. Theisen, and D. Verney

Subjects
General Physics and Astronomy
Published
2022
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27. Pygmy dipole resonance in 124Sn populated by inelastic scattering of 17O

Author

L. Pellegri, A. Bracco, F.C.L. Crespi, S. Leoni, F. Camera, E.G. Lanza, M. Kmiecik, A. Maj, R. Avigo, G. Benzoni, N. Blasi, C. Boiano, S. Bottoni, S. Brambilla, S. Ceruti, A. Giaz, B. Million, A.I. Morales, R. Nicolini, V. Vandone, O. Wieland, D. Bazzacco, P. Bednarczyk, M. Bellato, B. Birkenbach, D. Bortolato, B. Cederwall, L. Charles, M. Ciemala, G. De Angelis, P. Désesquelles, J. Eberth, E. Farnea, A. Gadea, R. Gernhäuser, A. Görgen, A. Gottardo, J. Grebosz, H. Hess, R. Isocrate, J. Jolie, D. Judson, A. Jungclaus, N. Karkour, M. Krzysiek, E. Litvinova, S. Lunardi, K. Mazurek, D. Mengoni, C. Michelagnoli, R. Menegazzo, P. Molini, D.R. Napoli, A. Pullia, B. Quintana, F. Recchia, P. Reiter, M.D. Salsac, B. Siebeck, S. Siem, J. Simpson, P.-A. Söderström, O. Stezowski, Ch. Theisen, C. Ur, J.J. Valiente Dobon, and M. Zieblinski

Subjects
Physics, QC1-999
Abstract

The γ decay from the high-lying states of 124Sn was measured using the inelastic scattering of 17O at 340 MeV. The emitted γ rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented ΔE–E silicon telescopes. The angular distribution was measured both for the γ rays and the scattered 17O ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (γ,γ′) and (α,α′γ) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1− excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density. Keywords: Low-lying electric dipole excitations, 124Sn, Isospin character

Published
2014
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28. New narrow resonances observed in the unbound nucleus F15

Author

V. Girard-Alcindor, A. Mercenne, I. Stefan, F. de Oliveira Santos, N. Michel, M. Płoszajczak, M. Assié, A. Lemasson, E. Clément, F. Flavigny, A. Matta, D. Ramos, M. Rejmund, J. Dudouet, D. Ackermann, P. Adsley, M. Assunção, B. Bastin, D. Beaumel, G. Benzoni, R. Borcea, A. J. Boston, D. Brugnara, L. Cáceres, B. Cederwall, I. Celikovic, V. Chudoba, M. Ciemala, J. Collado, F. C. L. Crespi, G. D'Agata, G. De France, F. Delaunay, C. Diget, C. Domingo-Pardo, J. Eberth, C. Fougères, S. Franchoo, F. Galtarossa, A. Georgiadou, J. Gibelin, S. Giraud, V. González, N. Goyal, A. Gottardo, J. Goupil, S. Grévy, V. Guimaraes, F. Hammache, L. J. Harkness-Brennan, H. Hess, N. Jovančević, D. S. Judson Oliver, O. Kamalou, A. Kamenyero, J. Kiener, W. Korten, S. Koyama, M. Labiche, L. Lalanne, V. Lapoux, S. Leblond, A. Lefevre, C. Lenain, S. Leoni, H. Li, A. Lopez-Martens, A. Maj, I. Matea, R. Menegazzo, D. Mengoni, A. Meyer, B. Million, B. Monteagudo, P. Morfouace, J. Mrazek, M. Niikura, J. Piot, Zs. Podolyak, C. Portail, A. Pullia, B. Quintana, F. Recchia, P. Reiter, K. Rezynkina, T. Roger, J. S. Rojo, F. Rotaru, M. D. Salsac, A. M. Sánchez Benítez, E. Sanchis, M. Şenyigit, N. de Séréville, M. Siciliano, J. Simpson, D. Sohler, O. Sorlin, M. Stanoiu, C. Stodel, D. Suzuki, C. Theisen, D. Thisse, J. C.Thomas, P. Ujic, J. J. Valiente-Dobón, and M. Zielińska

Published
2022
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29. Early childhood factors in the development of oral health behaviours in adolescence: A structural equation modelling approach

Author

Natália C. Costa, Jessica K. Knorst, Bruna Brondani, Gabriele R. Menegazzo, Fausto M. Mendes, Diego M. Ardenghi, and Thiago M. Ardenghi

Subjects
Public Health, Environmental and Occupational Health, General Dentistry
Abstract

Oral health behaviour is a learning process that begins in the early years of an individual's life. The aim of this study was to evaluate the associations between demographic, socioeconomic, and psychosocial factors and oral health behaviours during the transition period from childhood to adolescence.This was a cohort study with a follow-up of 7 years. The baseline assessment occurred in 2010 with a random sample of 639 preschool children from southern Brazil. Demographic, socioeconomic and psychosocial oral health conditions were assessed at baseline. Oral health habit variables were collected at follow-up and included questions regarding dental care and oral hygiene behaviours. Structural equation modelling was performed to assess the direct and indirect relationships between predictors at baseline in oral health behaviours at follow-up.A total of 449 children were re-examined at follow-up (70.3% cohort retention rate). Factors directly related to poorer oral health behaviours (lower use of dental services, dental visits for emergency reasons and lower frequency of toothbrushing) were lower household income, lower maternal education, lower frequency of visits to neighbours or friends, and male sex. Considering indirect pathways, the household income and maternal education at baseline influenced oral health behaviours at follow-up via visits to neighbours or friends.Our findings suggest that household income, maternal education and social capital play an important role in the development of oral health behaviours during the transition from childhood to adolescence. Acquisition of healthy oral behaviours is an important factor to consider in childhood. With this knowledge, public health policies can be developed to intervene in specific causal factors and improve oral health during this transitional period.

Published
2022

30. Evidence for spherical-oblate shape coexistence in Tc-87

Author

X. Liu, B. Cederwall, C. Qi, R. A. Wyss, Ö. Aktas, A. Ertoprak, W. Zhang, E. Clément, G. de France, D. Ralet, A. Gadea, A. Goasduff, G. Jaworski, I. Kuti, B. M. Nyakó, J. Nyberg, M. Palacz, R. Wadsworth, J. J. Valiente-Dobón, H. Al-Azri, A. Ataç Nyberg, T. Bäck, G. de Angelis, M. Doncel, J. Dudouet, A. Gottardo, M. Jurado, J. Ljungvall, D. Mengoni, D. R. Napoli, C. M. Petrache, D. Sohler, J. Timár, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, A. J. Boston, H. C. Boston, I. Burrows, L. Charles, M. Ciemala, F. C. L. Crespi, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Eberth, N. Erduran, S. Ertürk, V. González, J. Goupil, H. Hess, T. Huyuk, A. Jungclaus, W. Korten, A. Lemasson, S. Leoni, A. Maj, R. Menegazzo, B. Million, R. M. Perez-Vidal, Zs. Podolyàk, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, J. Simpson, O. Stezowski, C. Theisen, M. Zielińska, Swedish Research Council, Science and Technology Facilities Council (UK), National Science Centre (Poland), National Research, Development and Innovation Office (Hungary), Ministerio de Ciencia e Innovación (España), Generalitat Valenciana, China Scholarship Council, and Liu, X.

Subjects
Subatomär fysik, Atom and Molecular Physics and Optics, Subatomic Physics, Atom- och molekylfysik och optik
Abstract

6 pags., 8 figs., 1 tab., Excited states in the neutron-deficient nucleus Tc87 have been studied via the fusion-evaporation reaction Fe54(Ar36,2n1p)Tc87 at 115 MeV beam energy. The AGATA γ-ray spectrometer coupled to the DIAMANT, NEDA, and Neutron Wall detector arrays for light-particle detection was used to measure the prompt coincidence of γ rays and light particles. Six transitions from the deexcitation of excited states belonging to a new band in Tc87 were identified by comparing γ-ray intensities in the spectra gated under different reaction channel selection conditions. The constructed level structure was compared with the shell model and total Routhian surface calculations. The results indicate that the new band structure in Tc87 is built on a spherical configuration, which is different from that assigned to the previously identified oblate yrast rotational band., This work was supported by the Swedish Research Council under Grants No. 621-2014-5558 and No. 2019-04880; the EU 7th Framework Programme, Integrating Activities Transnational Access, Project No. 262010 ENSAR; the UK STFC under Grants No. ST/L005727/1 and No. ST/P003885/1; the Polish National Science Centre, Grants No. 2016/22/M/ST2/00269 and No. 2017/25/B/ST2/01569; COPIN-INFN, COPIN-IN2P3, and COPIGAL projects; the National Research, Development and Innovation Fund of Hungary (Project No. K128947); the European Regional Development Fund (Contract No. GINOP-2.3.3-15-2016-00034); the Hungarian National Research, Development and Innovation Office, NKFIH, Contract No. PD124717; the Ministerio de Ciencia e Innovación and Generalitat Valenciana, Spain, under the Grants No. SEV-2014-0398 and No. FPA2017-84756-C4; PROMETEO/2019/005; and by the EU FEDER funds. X.L. gratefully acknowledges support from the China Scholarship Council, Grant No. 201700260183, for his stay in Sweden. We acknowledge the support from the AGATA Collaboration and thank the GANIL staff for excellent technical support and operation

Published
2022

31. Reinterpretation of excited states in Po212 : Shell-model multiplets rather than α -cluster states

Author

B. Million, E. Dupont, Bertrand Jacquot, R. Menegazzo, M. Ciemala, M. Zielińska, R. M. Perez-Vidal, L. J. Harkness-Brennan, D. Mengoni, Vicente González, W. Korten, D. Kocheva, D. Ralet, D. R. Napoli, P. Reiter, J. Eberth, Zs. Podolyák, A. Astier, B. Birkenbach, C. Michelagnoli, G. Tocabens, A. Perea, J. Dudouet, Ch. Lorenz, A. Bracco, A. Maj, M. Jurado, Begoña Quintana, A. Fernández, H. C. Boston, J. Ropert, J. Ljungvall, L. Ménager, Dirk Rudolph, G. Benzoni, H. Naïdja, E. Nácher, A. Korichi, A. Jungclaus, K. Wimmer, J. J. Valiente-Dobón, C. Houarner, A. Gadea, Johan Nyberg, J. Collado, A. Pullia, A. Gargano, Hans-Jurgen E. Hess, A. J. Boston, Emyr Clement, J. Goupil, A. Såmark-Roth, Enrique Sanchis, Diego Barrientos, S. Leoni, G. Frémont, N. Lalović, F. Saillant, D. S. Judson, O. Stezowski, A. Lemasson, C. Spitaels, S. Ansari, G. S. Simpson, D. M. Cullen, A. Illana, N. Redon, Luis Sarmiento, C. M. Petrache, G. Rainovski, Ch. Theisen, H. J. Li, C. Domingo-Pardo, and Pavel Golubev

Subjects
Reinterpretation, Physics, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, SHELL model, Cluster (physics), Atomic physics, 010306 general physics, 01 natural sciences
Published
2021
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33. Direct Measurement of the C13(α,n)O16 Cross Section into the s -Process Gamow Peak

Author

Rosanna Depalo, A. Best, D. Piatti, G. Gervino, G. F. Ciani, T. Chillery, P. Colombetti, F. Ferraro, E. Masha, Luigi Schiavulli, A. Boeltzig, R. Menegazzo, Tamás Szücs, Z. Elekes, Oscar Straniero, Gianluca Imbriani, K. Stöckel, Marialuisa Aliotta, A. Guglielmetti, Filippo Terrasi, R. Perrino, A. Di Leva, J. Balibrea-Correa, László Csedreki, T. Davinson, Sandra Zavatarelli, Paolo Prati, Gy. Gyürky, F. Cavanna, P. Corvisiero, C. Gustavino, E. M. Fiore, Zs. Fülöp, V. Mossa, M. P. Takács, Paola Marigo, Carlo Bruno, Maria Lugaro, Antonio Caciolli, V. Paticchio, A. Formicola, Francesco Barile, F. R. Pantaleo, Diego Vescovi, M. Junker, Carlo Broggini, Sergio Cristallo, D. Rapagnani, and Daniel Bemmerer

Subjects
Physics, 010308 nuclear & particles physics, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Nuclear physics, Stars, Cross section (physics), 13. Climate action, Nucleosynthesis, 0103 physical sciences, Asymptotic giant branch, Neutron source, Production (computer science), Nuclear Experiment, s-process, 010303 astronomy & astrophysics, Energy (signal processing)
Abstract

One of the main neutron sources for the astrophysical s process is the reaction ^{13}C(α,n)^{16}O, taking place in thermally pulsing asymptotic giant branch stars at temperatures around 90 MK. To model the nucleosynthesis during this process the reaction cross section needs to be known in the 150-230 keV energy window (Gamow peak). At these sub-Coulomb energies, cross section direct measurements are severely affected by the low event rate, making us rely on input from indirect methods and extrapolations from higher-energy direct data. This leads to an uncertainty in the cross section at the relevant energies too high to reliably constrain the nuclear physics input to s-process calculations. We present the results from a new deep-underground measurement of ^{13}C(α,n)^{16}O, covering the energy range 230-300 keV, with drastically reduced uncertainties over previous measurements and for the first time providing data directly inside the s-process Gamow peak. Selected stellar models have been computed to estimate the impact of our revised reaction rate. For stars of nearly solar composition, we find sizeable variations of some isotopes, whose production is influenced by the activation of close-by branching points that are sensitive to the neutron density, in particular, the two radioactive nuclei ^{60}Fe and ^{205}Pb, as well as ^{152}Gd.

Published
2021
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34. Evidence for enhanced neutron-proton correlations from the level structure of the N=Z+1 nucleus Tc444387

Author

X. Liu, B. Cederwall, C. Qi, R. A. Wyss, Ö. Aktas, A. Ertoprak, W. Zhang, E. Clément, G. de France, D. Ralet, A. Gadea, A. Goasduff, G. Jaworski, I. Kuti, B. M. Nyakó, J. Nyberg, M. Palacz, R. Wadsworth, J. J. Valiente-Dobón, H. Al-Azri, A. Ataç Nyberg, T. Bäck, G. de Angelis, M. Doncel, J. Dudouet, A. Gottardo, M. Jurado, J. Ljungvall, D. Mengoni, D. R. Napoli, C. M. Petrache, D. Sohler, J. Timár, D. Barrientos, P. Bednarczyk, G. Benzoni, B. Birkenbach, A. J. Boston, H. C. Boston, I. Burrows, L. Charles, M. Ciemala, F. C. L. Crespi, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Eberth, N. Erduran, S. Ertürk, V. González, J. Goupil, H. Hess, T. Huyuk, A. Jungclaus, W. Korten, A. Lemasson, S. Leoni, A. Maj, R. Menegazzo, B. Million, R. M. Perez-Vidal, Zs. Podolyàk, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, J. Simpson, O. Stezowski, C. Theisen, and M. Zielińska

Subjects
Physics, Proton, Spectrometer, 010308 nuclear & particles physics, Isoscalar, Nuclear Theory, 01 natural sciences, Charged particle, Excited state, 0103 physical sciences, Level structure, Neutron, AGATA, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

The low-lying excited states in the neutron-deficient $N = Z + 1$ nucleus $^{87}_{43}$Tc$_{44}$ have been studied via the fusion-evaporation reaction $^{54}$Fe $(^{36}Ar, 2n1p)$ $^{87}$Tc at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt γ rays, neutrons, and charged particles emitted in the reaction. A level scheme of $^{87}$Tc from the $(9/2^+_{g.s})$ state to the $( 33 / 2^+_1$) state was established based on six mutually coincident γ -ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at $ℏω ≈ 0.50$ MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around $N=44$ is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the $N=Z$ line.

Published
2021
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35. Low-energy resonances in the O18 ( p,γ)19F reaction

Author

Rosanna Depalo, A. Best, Antonio Caciolli, K. Stöckel, I. Kochanek, Davide Trezzi, Gianluca Imbriani, R. Perrino, E. Masha, Luigi Schiavulli, F. R. Ferraro, M. P. Takács, V. Paticchio, A. Formicola, F. R. Pantaleo, Francesco Barile, T. Chillery, T. Davinson, Daniel Bemmerer, G. F. Ciani, Tamás Szücs, A. Guglielmetti, László Csedreki, D. Rapagnani, Oscar Straniero, A. Di Leva, Sandra Zavatarelli, Gy. Gyürky, Michael Wiescher, G. Gervino, A. Boeltzig, Zs. Fülöp, V. Mossa, Marialuisa Aliotta, J. Balibrea-Correa, Carlo Bruno, E. M. Fiore, M. Junker, C. Gustavino, G. D'Erasmo, F. Cavanna, Paolo Prati, Carlo Broggini, M. Lugaro, Raffaele Buompane, Richard deBoer, R. Menegazzo, D. Piatti, Z. Elekes, and P. Corvisiero

Subjects
Reaction rate, Nuclear reaction, Physics, Nucleosynthesis, Presolar grains, Nuclear astrophysics, Stellar atmosphere, Asymptotic giant branch, Resonance, Atomic physics
Abstract

Background: Shell hydrogen burning during the asymptotic giant branch (AGB) phase through the oxygen isotopes has been indicated as a key process that is needed to understand the observed O 18 / O 16 relative abundance in presolar grains and in stellar atmospheres. This ratio is strongly influenced by the relative strengths of the reactions O 18 ( p , α ) N 15 and O 18 ( p , γ ) F 19 in low-mass AGB stars. While the former channel has been the focus of a large number of measurements, the ( p , γ ) reaction path has only recently received some attention and its stellar reaction rate over a wide temperature range rests on only one measurement. Purpose: Our aim is the direct measurement of states in F 19 as populated through the reaction O 18 ( p , γ ) F 19 to better determine their influence on the astrophysical reaction rate, and more generally to improve the understanding of the nuclear structure of F 19 .Method: Branchings and resonance strengths were measured in the proton energy range E p lab = 150 – 400 keV , using a high-purity germanium detector inside a massive lead shield. The measurement took place in the ultra-low-background environment of the Laboratory for Underground Nuclear Astrophysics (LUNA) experiment at the Gran Sasso National Laboratory, leading to a highly increased sensitivity. Results: The uncertainty of the γ branchings and strengths was improved for all four resonances in the studied energy range; many new transitions were observed in the case of the 334 keV resonance, and individual γ decays of the 215 keV resonance were measured for the first time. In addition a number of transitions to intermediate states that decay through α emission were identified. The strengths of the observed resonances are generally in agreement with literature values. Conclusions: Our measurements substantially confirm previous determinations of the relevant resonance strengths. Therefore the O 18 ( p , γ ) F 19 reaction rate does not change with respect to the reaction rate reported in the compilations commonly adopted in the extant computations of red-giant branch and AGB stellar models. Nevertheless, our measurements definitely exclude a nonstandard scenario for the fluorine nucleosynthesis and a nuclear physics solution for the O 18 depletion observed in Group 2 oxygen-rich stardust grains.

Published
2021
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36. High-spin intruder states in the mirror nuclei S31 and P31

Author

M. Rocchini, M. Siciliano, R. Menegazzo, P. R. John, D. Bazzacco, J. J. Valiente-Dobón, A. Mentana, D. A. Testov, A. Nannini, G. Colucci, A. Gozzelino, F. Recchia, D. Mengoni, F. Galtarossa, K. Hadynska-Klek, D. R. Napoli, A. Boso, M. Palacz, V. Modamio, F. Nowacki, M. Cottini, S. M. Lenzi, G. Jaworski, S. Lunardi, G. de Angelis, and A. Goasduff

Subjects
Physics, Condensed matter physics, 010308 nuclear & particles physics, 0103 physical sciences, Mirror nuclei, 010306 general physics, Spin (physics), 01 natural sciences
Published
2021
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37. Probing isospin mixing with the giant dipole resonance in the Zn-60 compound nucleus

Author

S. Pascu, J. Kaur, G. Gosta, M. Rocchini, A. Montaner, G. de Angelis, A. Nannini, R. Menegazzo, F. Galtarossa, S. Capra, D. Mengoni, G. Pasqualato, M. Ciemala, C. Porzio, F. Camera, S. M. Lenzi, A. Boso, D. Filipescu, V. Zamfir, J. Yang, A. Giaz, A. Gadea, S. Riboldi, A. Gottardo, S. Brambilla, Tuncay Bayram, B. Wasilewska, A. Maj, D. Brugnara, D. Bazzacco, F. C. L. Crespi, S. Ceruti, J. J. Valiente-Dobón, N. Blasi, M. Siciliano, T. Marchi, N. Marginean, P. R. John, M. Kmiecik, D. R. Napoli, R. Raabe, G. Jaworski, A. Bracco, O. Wieland, G. Benzoni, S. Leoni, A. Mentana, F. Recchia, I. Zanon, B. Million, A. Goasduff, Dmitry Testov, N. Marchini, S. Ziliani, M. Zieblinski, O. Poleshchuk, A. Gozzelino, T. Glodariu, and D. Ghita

Subjects
Physics, Science & Technology, 010308 nuclear & particles physics, SYMMETRY, WIDTH, Resonance, 01 natural sciences, 3. Good health, Dipole, medicine.anatomical_structure, Physics, Nuclear, Isospin, 0103 physical sciences, Physical Sciences, medicine, Atomic physics, 010306 general physics, Nucleus, Mixing (physics), BREAKING
Abstract

ispartof: PHYSICAL REVIEW C vol:103 issue:4 status: published

Published
2021

38. STUDY OF THE TIME DEPENDENCE OF RADIOACTIVITY

Author

E Bellotti, C. Broggini, G. Di Carlo, M. Laubenstein, and R. Menegazzo

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

The activity of a 137Cs source was measured using a germanium detector installed deep underground in the Gran Sasso Laboratory. In total about 5100 energy spectra, one hour measuring time each, were collected and used to search for time variations of the decay constant with periods from a few hours to 1 year. No signal with amplitude larger than 9.6 × 10−5 at 95% C.L. was detected. These limits are more than one order of magnitude lower than the values on the oscillation amplitude reported in the literature. The same data give a value of 29.96±0.08 years for the 137Cs half life, which is in good agreement with the world mean value of 30.05 ± 0.08 years.

Published
2013
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39. Onset of triaxial deformation in Zn66 and properties of its first excited 0+ state studied by means of Coulomb excitation

Author

M. Matejska-Minda, M. Siciliano, M. Zielińska, L. Ramina, D. A. Testov, P. Sona, D. T. Doherty, K. Hadyńska-Klȩk, F. Nowacki, A. Boso, F. Recchia, G. De Gregorio, F. Galtarossa, P. Cocconi, M. Rampazzo, P. R. John, J. J. Valiente-Dobón, M. Komorowska, P. J. Napiorkowski, M. Rocchini, D. Rosso, Massimo Chiari, Tomás R. Rodríguez, N. Marchini, R. Menegazzo, M. Ottanelli, A. Gargano, A. Goasduff, A. Nannini, D. R. Napoli, B. Melon, D. Bazzacco, A. Perego, D. Mengoni, S. Riccetto, G. Jaworski, G. Benzoni, and H. Naïdja

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Nuclear structure, Magnetic monopole, Coulomb excitation, 01 natural sciences, Matrix (mathematics), Excited state, 0103 physical sciences, Quadrupole, Atomic physics, 010306 general physics, Excitation
Abstract

The electromagnetic structure of Zn66 at low excitation energy was investigated via low-energy Coulomb excitation at INFN Legnaro National Laboratories, using the Gamma Array of Legnaro Infn Laboratories for nuclEar spectrOscopy (GALILEO) γ-ray spectrometer coupled to the SPIDER (Silicon PIe DEtectoR). A set of reduced E2, E3, and M1 matrix elements was extracted from the collected data using the gosia code, yielding 12 reduced transition probabilities between the low-spin states and the spectroscopic quadrupole moment of the 21+ state. The B(E2) values for transitions depopulating the 02+ state have been determined for the first time, allowing for the lifetime of this state to be deduced and, consequently, the ρ2(E0;02+→01+) monopole transition strength to be extracted. In addition, the B(E3;31−→01+) value has been determined for the first time in a Coulomb excitation experiment. The obtained results resolve the existing discrepancies between literature lifetimes and demonstrate that Zn66 cannot be described by using simple collective models. Therefore, new state-of-the-art beyond-mean-field and large-scale shell-model calculations were performed in order to interpret the structure of this nucleus. Both the experimental and theoretical results suggest that the triaxial degree of freedom has an important impact on electromagnetic properties of Zn66, while the unique features of the 02+ state indicate its distinct and rather isolated structure.

Published
2021
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40. The GALILEO γ-ray array at the Legnaro National Laboratories

Author

R. Menegazzo, I. Zanon, F. Veronese, D.A. Testov, J. Ha, N. Bez, B. Million, G. Pasqualato, Alberto Pullia, M. Biasotto, L. Ramina, S. Bottoni, C. A. Ur, M. L. Cortés, D. Mengoni, S. Coelli, G. Gosta, C. Fanin, M. Siciliano, A. Saltarelli, D. Bazzacco, D. Tomasella, J. J. Valiente-Dobón, S. Leoni, M. Romanato, S. Ventura, A. Gadea, N. Toniolo, Marco Bellato, Diego Barrientos, S. Brambilla, D. Brugnara, R.M. Pérez-Vidal, F. Recchia, F. C. L. Crespi, F.J. Egea, S. Lunardi, S. Capra, M. Rebeschini, S. Fantinel, G. Jaworski, A. Bracco, M. Gulmini, G. Rampazzo, M. Scarcioffolo, N. Blasi, J. Pellumaj, S. Pigliapoco, G. Benzoni, V. Volpe, P. Cocconi, A. Boso, O. Wieland, K. Hadyńska-Klȩk, E.R. Gamba, A. Capsoni, A. Gambalonga, E. Viscione, F. Camera, G. de Angelis, A. Nannini, Roberto Isocrate, C. Boiano, A. Illana, M. Rocchini, G. Zhang, A. Gottardo, A. Goasduff, C. Gesmundo, P. R. John, N. Marchini, S. Ziliani, K. Rezynkina, D. R. Napoli, E. Gregor, A. Gozzelino, D. Rosso, M. Rampazzo, V. Modamio, M. Polettini, M. Magalini, F. Tomasi, S. M. Lenzi, and C. Porzio

Subjects
Physics, Nuclear and High Energy Physics, Silicon, business.industry, Instrumentation, High-resolution γ-ray spectroscopy, Detector, Neutron, DAQ, Electronics, HPGe, Semiconductor detector, Optics, Data acquisition, Galileo (vibration training), business, Hpge detector
Abstract

GALILEO, a new 4 π high-resolution γ -detection array, based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories. The GALILEO array greatly benefits from a fully-digital read-out chain, customized DAQ, and a variety of complementary detectors to improve the resolving power by the detection of particles, ions or high-energy γ -ray transitions. In this work, a full description of the array, including electronics and DAQ, is presented together with its complementary instrumentation.

Published
2021

41. Transition probabilities in 31P and 31S : A test for isospin symmetry

Author

E. Sahin, S. Iliev, S. M. Lenzi, Dimitar Tonev, S. Lunardi, H.-F. Wirth, M. S. Yavahchova, N. Marginean, P. Pavlov, H. Laftchiev, R. Menegazzo, C. A. Ur, E. Farnea, R. P. Singh, G. de Angelis, F. Recchia, E. Geleva, A. Gadea, P. G. Bizzeti, C. Y. He, I.L. Pantaleev, D. R. Napoli, I. Deloncle, M. Stoyanova, Heikki Penttilä, G. De Gregorio, F. Nowacki, D.T. Dimitrov, N. Goutev, A. Demerdjiev, R. Orlandi, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Tonev, D., de Angelis, G., Deloncle, I., Goutev, N., De Gregorio, G., Pavlov, P., Pantaleev, I. L., Iliev, S., Yavahchova, M. S., Bizzeti, P. G., Demerdjiev, A., Dimitrov, D. T., Farnea, E., Gadea, A., Geleva, E., He, C. Y., Laftchiev, H., Lenzi, S. M., Lunardi, S., Marginean, N., Menegazzo, R., Napoli, D. R., Nowacki, F., Orlandi, R., Penttila, H., Recchia, F., Sahin, E., Singh, R. P., Stoyanova, M., Ur, C. A., and Wirth, H. -F.

Subjects
Nuclear and High Energy Physics, Lifetime measurement, Isoscalar, QC1-999, Lifetime measurements, lifetime measurements, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Resonance (particle physics), Isospin symmetry, transition probabilities, Nuclear physics, Microscopic multiphonon model, Mirror nuclei, mirror nuclei, 0103 physical sciences, Transition probabilities, 010306 general physics, mirror, Physics, Isovector, 010308 nuclear & particles physics, 31S, Charge (physics), 31P, Symmetry (physics), Charged particle, isospin symmetry, Isospin, microscopic multiphonon model, nuclei, ydinfysiikka
Abstract

International audience; Excited states in the mirror nuclei 31P and 31S were populated in the 1p and 1n exit channels of the reaction 20Ne + 12C, at a beam energy of 33 MeV. The 20Ne beam was delivered for the first time by the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Angular correlations of coincident γ-rays and Doppler-shift attenuation lifetime measurements were performed using the multi-detector array GASP in conjunction with the EUCLIDES charged particle detector. In the observed B(E1) strengths, the isoscalar component, amounting to 24% of the isovector one, provides strong evidence for breaking of the isospin symmetry in the A=31 mass region. Self-consistent beyond mean field calculations using Equation of Motion method based on a chiral potential and including two- and three-body forces reproduce well the experimental B(E1) strengths, reinforcing our conclusion. Coherent mixing from higher-lying states involving the Giant Isovector Monopole Resonance accounts well for the effect observed. The breaking of the isospin symmetry originates from the violation of the charge symmetry of the two- and three-body parts of the potential, only related to the Coulomb interaction.

Published
2021
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42. Octupole correlations near Te 110

Author

Maria Doncel, D. Bazzacco, A. Goasduff, S. M. Lenzi, G. Jaworski, G. de Angelis, F. Didierjean, L. M. Robledo, Huan Liu, R. Menegazzo, M. Siciliano, F. Nowacki, D. Mengoni, D. A. Testov, S. Lunardi, Tomás R. Rodríguez, B. Saygi, Bo Cederwall, Yu. Sobolev, F. Recchia, S. Bakes, G. Colucci, M. Rocchini, P. Čolović, J. A. Dueñas, C. Boiano, G. Pasqualato, Suzana Szilner, A. Mentana, Magda Cicerchia, A. Gozzelino, K. Hadynska-Klek, A. Boso, F. Galtarossa, P. R. John, J. J. Valiente-Dobón, D. R. Napoli, S. Frauendorf, S. Riccetto, and UAM. Departamento de Física Teórica

Subjects
Physics, Engineering management, Spin, Work (electrical), 010308 nuclear & particles physics, Chiral, 0103 physical sciences, Física, 010306 general physics, 01 natural sciences, Shell Model, Nucleus, Band
Abstract

The lifetime of the 2(+) and 9(-), 11(-), 13(-), 15(-) states in the neutron-deficient Te-110 was measured for the first time using the recoil distance Doppler shift technique. The reported value of the reduced transition probability B(E2; 0(g.s)(+) -> 2(+)) = 4.3(8) x 10(3) e(2) f m(4) supports the systematic for even-mass Te isotopes and was interpreted g.s in the framework of the large-scale shell model and cranked shell model calculations. The measured reduced transition probabilities in the negative-parity yrast band revealed the upward trend towards the high spins. The enhanced collectivity is discussed in terms of the tilted axis cranking approach and the symmetry configuration mixing method with the Gogny D1S interaction., DoE [DE-FG02-95ER4093]; Spanish MICINN [PGC2018-094583-B-I00], The authors would like to thank the technical staff of the LNL Legnaro facility for their assistance in providing excellent operation of the XTU-tandem accelerator. The authors wish to acknowledge the support of local engineers P. Cocconi and R. Isocrate. The work was partially supported by the DoE Grant No. DE-FG02-95ER4093 and Spanish MICINN Grant No. PGC2018-094583-B-I00.

Published
2021

43. Underground experimental study finds no evidence of low-energy resonance in theLi6(p,γ)Be7reaction

Author

Gianluca Imbriani, A. Boeltzig, A. Gnech, V. Mossa, T. Davinson, Carlo Bruno, R. Menegazzo, Laura Elisa Marcucci, G. F. Ciani, M. P. Takács, Antonio Caciolli, Oscar Straniero, F. Cavanna, Gy. Gyürky, M. Junker, Marialuisa Aliotta, Rosanna Depalo, A. Best, T. Chillery, Z. Elekes, C. Gustavino, E. Masha, A. Di Leva, Luigi Schiavulli, G. Gervino, P. Corvisiero, V. Paticchio, A. Formicola, Zs. Fülöp, K. Stöckel, Paolo Prati, M. Lugaro, D. Piatti, A. Guglielmetti, László Csedreki, F. R. Pantaleo, Carlo Broggini, I. Kochanek, Sandra Zavatarelli, Paola Marigo, Daniel Bemmerer, R. Perrino, F. R. Ferraro, Tamás Szücs, and E. M. Fiore

Subjects
Physics, Low energy, Resonance, Atomic physics
Published
2020
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44. A powerful combination measurement for exploring the fusion reaction mechanisms induced by weakly bound nuclei

Author

Y. J. Yao, A. Boso, S. M. Lenzi, D. Mengoni, E. T. Li, G. L. Zhang, F. Recchia, F. Galtarossa, D. R. Napoli, G. X. Zhang, D. Bazzacco, D. A. Testov, Shi-Peng Hu, P. R. John, J. J. Valiente-Dobón, Alain Goasduff, X. Hao, R. Menegazzo, M. Siciliano, H. B. Sun, Huan-Qiao Zhang, and D. De Angelis

Subjects
Physics, Nuclear and High Energy Physics, Reaction mechanism, Fusion, Coincidence measurement, Spectrometer, 010308 nuclear & particles physics, Projectile, Charged-particle detector, Breakup, 01 natural sciences, Molecular physics, Coincidence, Charged particle, γ-ray detector, Fusion mechanisms, Instrumentation, 0103 physical sciences, Nuclear fusion, Nuclear Experiment, 010306 general physics
Abstract

The GALILEO array is a high-efficiency γ -ray spectrometer, resident at the Legnaro National Laboratory (LNL)in Italy, and it is currently used in combination with the Si-ball EUCLIDES for the detection of charged-particles. The combined setup was used in the 6 Li+89Y experiment with incident energies of 22 MeV and 34 MeV to investigate the influence of breakup and transfer of weakly bound projectile on the fusion process. Using the coincidence by the charged particles and γ -rays, the different reaction channels can be clearly identified and the different reaction mechanisms can be clearly studied. It is shown that this facility can be used well to explore the fusion reaction mechanisms induced by weakly bound nuclei.

Published
2019
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45. Testing ab initio nuclear structure in neutron-rich nuclei: Lifetime measurements of second 2+ state in C16 and O20

Author

M. Ciemała, S. Ziliani, F. C. L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Oryńczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grębosz, M. N. Harakeh, Ł. W. Iskra, B. Jacquot, A. Karpov, M. Kicińska-Habior, Y. Kim, M. Kmiecik, A. Lemasson, S. M. Lenzi, M. Lewitowicz, H. Li, I. Matea, K. Mazurek, C. Michelagnoli, M. Matejska-Minda, B. Million, C. Müller-Gatermann, V. Nanal, P. Napiorkowski, D. R. Napoli, R. Palit, M. Rejmund, Ch. Schmitt, M. Stanoiu, I. Stefan, E. Vardaci, B. Wasilewska, O. Wieland, M. Zieblinski, M. Zielińska, A. Ataç, D. Barrientos, B. Birkenbach, A. J. Boston, B. Cederwall, L. Charles, J. Collado, D. M. Cullen, P. Désesquelles, C. Domingo-Pardo, J. Dudouet, J. Eberth, V. González, J. Goupil, L. J. Harkness-Brennan, H. Hess, D. S. Judson, A. Jungclaus, W. Korten, M. Labiche, A. Lefevre, R. Menegazzo, D. Mengoni, J. Nyberg, R. M. Perez-Vidal, Zs. Podolyak, A. Pullia, F. Recchia, P. Reiter, F. Saillant, M. D. Salsac, E. Sanchis, O. Stezowski, Ch. Theisen, J. J. Valiente-Dobón, J. D. Holt, J. Menéndez, A. Schwenk, and J. Simonis

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Nuclear structure, Ab initio, Neutron, State (functional analysis), Atomic physics, 010306 general physics, 7. Clean energy, 01 natural sciences, Nuclear theory
Abstract

To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2(+) state in neutron-rich O-20, tau(2(2)(+)) = 150(-30)(+80) fs, and an estimate for the lifetime of ...

Published
2020
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46. Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus Ru88

Author

Eric Clément, B. Birkenbach, M. Zielińska, B. Million, M. Doncel, C. Domingo-Pardo, F. Recchia, J. Ljungvall, R. M. Perez-Vidal, Torbjörn Bäck, P. Reiter, P. Bednarczyk, J. Simpson, D. Mengoni, J. J. Valiente-Dobón, A. Lemasson, W. Korten, W. Zhang, X. Liu, B. M. Nyako, A. J. Boston, J. Goupil, H. Al-Azri, Diego Barrientos, M. D. Salsac, F. C. L. Crespi, A. Jungclaus, A. Gadea, A. Maj, N. Erduran, P. Désesquelles, A. Gottardo, Ch. Theisen, T. Hüyük, János Timár, Alberto Pullia, Vicente González, L. Charles, Zs. Podolyák, R. Menegazzo, C. M. Petrache, D. M. Cullen, S. Erturk, A. Ataç Nyberg, M. Jurado, Herbert Hess, Chong Qi, O. Aktas, Bo Cederwall, István Kuti, D. R. Napoli, Johan Nyberg, Alain Goasduff, D. Ralet, Enrique Sanchis, A. Ertoprak, M. Palacz, F. Saillant, D. Sohler, O. Stezowski, R. Wadsworth, J. Dudouet, G. de Angelis, M. Ciemala, G. Jaworski, J. Eberth, H. C. Boston, G. Benzoni, I. Burrows, and S. Leoni

Subjects
Physics, Isovector, Isoscalar, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, Charged particle, Nuclear physics, 13. Climate action, Isospin, Excited state, 0103 physical sciences, Neutron detection, AGATA, Neutron, Nuclear Experiment, 010306 general physics
Abstract

The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide 88 44Ru44 has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in 88Ru were populated via the 54Fe(36Ar; 2n )88Ru fusion-evaporation reaction at the Grand Acc�el�erateur National d'Ions Lourds (GANIL) accelerator complex. The observed -ray cascade is assigned to 88Ru using clean prompt - -2-neutron coincidences in anti-coincidence with the detection of charged particles, con�rming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N > Z nuclides. The direct observation of such a \delayed" rotational alignment in a deformed N = Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.

Published
2020
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47. The baryon density of the Universe from an improved rate of deuterium burning

Author

Gianluca Imbriani, Gianpiero Mangano, F. Ferraro, K. Stöckel, Thomas Davinson, F. R. Pantaleo, F. Cavanna, R. Menegazzo, E. M. Fiore, E. Masha, Luigi Schiavulli, A. Best, M. Junker, M. P. Takács, Oscar Straniero, I. Kochanek, Daniel Bemmerer, Gyuri Gyürky, A. Guglielmetti, László Csedreki, D. Piatti, Ofelia Pisanti, Marialuisa Aliotta, Tamás Szücs, G. Gervino, Michele Viviani, A. Di Leva, R. Perrino, Laura Elisa Marcucci, Carlo Broggini, Sandra Zavatarelli, Paola Marigo, Davide Trezzi, Maria Lugaro, G. F. Ciani, V. Paticchio, A. Formicola, A. Boeltzig, Alejandro Kievsky, Zs. Fülöp, C. Gustavino, Rosanna Depalo, C. G. Bruno, Z. Elekes, Paolo Prati, Antonio Caciolli, Francesco Barile, V. Mossa, P. Corvisiero, T. Chillery, Mossa, V., Stockel, K., Cavanna, F., Ferraro, F., Aliotta, M., Barile, F., Bemmerer, D., Best, A., Boeltzig, A., Broggini, C., Bruno, C. G., Caciolli, A., Chillery, T., Ciani, G. F., Corvisiero, P., Csedreki, L., Davinson, T., Depalo, R., Di Leva, A., Elekes, Z., Fiore, E. M., Formicola, A., Fulop, Z., Gervino, G., Guglielmetti, A., Gustavino, C., Gyurky, G., Imbriani, G., Junker, M., Kievsky, A., Kochanek, I., Lugaro, M., Marcucci, L. E., Mangano, G., Marigo, P., Masha, E., Menegazzo, R., Pantaleo, F. R., Paticchio, V., Perrino, R., Piatti, D., Pisanti, O., Prati, P., Schiavulli, L., Straniero, O., Szucs, T., Takacs, M. P., Trezzi, D., Viviani, M., and Zavatarelli, S.

Subjects
Physics, Nuclear reaction, baryon density, primordial deuterium, big bang nucleosynthesis, nuclear astrophysics, Multidisciplinary, Proton, 010308 nuclear & particles physics, media_common.quotation_subject, nuclear astrophysics, big bang nucleosynthesis, 01 natural sciences, Cosmology, Universe, Nuclear physics, baryon density, Deuterium, Big Bang nucleosynthesis, primordial deuterium, 0103 physical sciences, Nuclear astrophysics, Neutrino, Nuclear Experiment, 010303 astronomy & astrophysics, media_common
Abstract

Light elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN)1,2. Among the light elements produced during BBN1,2, deuterium is an excellent indicator of cosmological parameters because its abundance is highly sensitive to the primordial baryon density and also depends on the number of neutrino species permeating the early Universe. Although astronomical observations of primordial deuterium abundance have reached percent accuracy3, theoretical predictions4,5,6 based on BBN are hampered by large uncertainties on the cross-section of the deuterium burning D(p,γ)3He reaction. Here we show that our improved cross-sections of this reaction lead to BBN estimates of the baryon density at the 1.6 percent level, in excellent agreement with a recent analysis of the cosmic microwave background7. Improved cross-section data were obtained by exploiting the negligible cosmic-ray background deep underground at the Laboratory for Underground Nuclear Astrophysics (LUNA) of the Laboratori Nazionali del Gran Sasso (Italy)8,9. We bombarded a high-purity deuterium gas target10 with an intense proton beam from the LUNA 400-kilovolt accelerator11 and detected the γ-rays from the nuclear reaction under study with a high-purity germanium detector. Our experimental results settle the most uncertain nuclear physics input to BBN calculations and substantially improve the reliability of using primordial abundances to probe the physics of the early Universe.

Published
2020
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48. Shape coexistence in neutron-deficient Hg188 investigated via lifetime measurements

Author

P. R. John, J. J. Valiente-Dobón, M. Zielińska, J. Pakarinen, I. Deloncle, A. Boso, B. Melon, D. Mengoni, D. A. Testov, B. de Canditiis, R. Menegazzo, Thomas Braunroth, A. Goasduff, S. M. Lenzi, Sophie Péru, A. Nannini, I. Zanon, G. Jaworski, G. de Angelis, A. Gadea, D. R. Napoli, F. Galtarossa, N. Cieplicka-Oryńczak, A. Vogt, B. Birkenbach, D. Ashad, F. Recchia, Liam Gaffney, G. Benzoni, W. Witt, D. Quero, D. Bazzacco, A. Gozzelino, P. Koseoglou, K. Hadyńska-Klȩk, F. Davide, M. Siciliano, P. K. Rath, J. Wiederhold, J. Libert, Magda Cicerchia, G. Colucci, Tomás R. Rodríguez, and M. Rocchini

Subjects
Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Nuclear structure, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Molecular physics, symbols.namesake, medicine.anatomical_structure, chemistry, Excited state, 0103 physical sciences, medicine, symbols, Neutron, 010306 general physics, Hamiltonian (quantum mechanics), Nucleus, Polonium
Abstract

Background: Shape coexistence in the Z≈82 region has been established in mercury, lead, and polonium isotopes. For even-even mercury isotopes with 100≤N≤106 multiple fingerprints of this phenomenon are observed, which seems to be no longer present for N≥110. According to a number of theoretical calculations, shape coexistence is predicted in the Hg188 isotope. Purpose: The aim of this work was to measure lifetimes of excited states in Hg188 to infer their collective properties, such as the deformation. Extending the investigation to higher-spin states, which are expected to be less affected by band-mixing effects, can provide additional information on the coexisting structures. Methods: The Hg188 nucleus was populated using two different fusion-evaporation reactions with two targets, Gd158 and Gd160, and a beam of S34 provided by the Tandem-ALPI accelerator complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the γ rays were detected using the GALILEO γ-ray spectrometer. Lifetimes of excited states were determined using the recoil-distance Doppler-shift method, employing the dedicated GALILEO plunger device. Results: Lifetimes of the states up to spin 16ℏ were measured and the corresponding reduced transition probabilities were calculated. Assuming two-band mixing and adopting, as done commonly, the rotational model, the mixing strengths and the deformation parameters of the unperturbed structures were obtained from the experimental results. In order to shed light on the nature of the observed configurations in the Hg188 nucleus, the extracted transition strengths were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach, limited to axial shapes, and the five-dimensional collective Hamiltonian, including the triaxial degree of freedom. Conclusions: The first lifetime measurement for states with spin ≥6 suggested the presence of an almost spherical structure above the 121+ isomer and allowed elucidating the structure of the intruder band. The comparison of the extracted B(E2) strengths with the two-band mixing model allowed the determination of the ground-state band deformation. Both beyond-mean-field calculations predict coexistence of a weakly deformed band with a strongly prolate-deformed one, characterized by elongation parameters similar to those obtained experimentally, but the calculated relative position of the bands and their mixing strongly differ.

Published
2020

49. g factor of the $12^+$K-isomer in $^{174}$W

Author

F. Camera, A. I. Morales, E. Vigezzi, O. Wieland, C. Michelagnoli, R. Menegazzo, P. Sona, J. J. Valiente-Dobón, D. Bazzacco, A. Nannini, S. Bottoni, Georgi P. Georgiev, D. R. Napoli, S. Ceruti, G. Bocchi, N. Blasi, Luna Pellegri, V. Modamio, C. A. Ur, M. Rocchini, S. Leoni, B. Million, R. Avigo, A. Perego, B. Melon, D. Mengoni, A. Bracco, G. Benzoni, Agnese Giaz, A. Gottardo, F. C. L. Crespi, M. Ottanelli, E. R. Gamba, P. R. John, S. Capra, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Laue-Langevin (ILL), ILL, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, g factor, Landé g-factor, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Tunnel effect, 0103 physical sciences, Quadrupole, Nuclear fusion, Atomic physics, 010306 general physics, Ground state, Dimensionless quantity
Abstract

The g factor of the $$12^+$$ K-isomer in $$^{174}$$ W has been measured by means of the time-differential perturbed angular distribution technique as $$g(12^+)=+0.304(11)$$ . In addition, the half-life of the isomer has been remeasured as $$T_{1/2}(12^+)=124(8)$$ ns, in agreement with the literature value and confirming the anomalous hindrance F of the E2 transition to the $$10^+$$ level of the ground state band with respect to the $$\gamma $$ -tunnelling model prediction. The measured g factor has been compared with estimates based on experimental g factors from odd-mass isotopes in the same mass region and with Nilsson model calculations. The results establish unique features of the $$12^+$$ K-isomer in $$^{174}$$ W, which can possess a non-pure intrinsic configuration and/or can be characterised by values of the intrinsic quadrupole moment $$Q_0$$ and the rotational g factor $$g_R$$ significantly different with respect to the majority of K-isomers at mass $$A \approx 180$$ .

Published
2020
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50. Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number

Author

Eric Clément, B. Birkenbach, A. I. Morales, D. Bazzacco, H. J. Wollersheim, J. J. Valiente-Dobón, D. M. Cullen, L. J. Harkness-Brennan, M. Kmiecik, Alberto Pullia, C. Domingo-Pardo, Luis Sarmiento, C. Nociforo, N. Goel, B. Bruyneel, G. Rainovski, M.D. Salsac, S. Pietri, Begoña Quintana, J. Simpson, Pavel Golubev, T. Habermann, Johan Nyberg, R. Menegazzo, S. Leoni, M. Reese, V. Yu. Ponomarev, A. Maj, T. Arici, A. Gottardo, N. Kurz, M. Górska, S. Brambilla, I. Kojouharov, E. Merchan, M. L. Cortés, Stefano Riboldi, Enrique Sanchis, N. Lalović, Vicente González, R. Avigo, Norbert Pietralla, P. Reiter, F. Camera, M. Labiche, Zs. Podolyák, J. Gerl, D. Ralet, F. Ameil, Andreas Görgen, A. Gadea, A. Bracco, A. Jungclaus, G. Benzoni, O. Stezowski, Dirk Rudolph, D. Curien, J. Eberth, H. C. Boston, S. Bottoni, W. Korten, F. C. L. Crespi, N. Blasi, H. Schaffner, D. Mengoni, M. Lettmann, G. Duchêne, Diego Barrientos, P. H. Regan, F. Didierjean, M. Ciemala, P. Bednarczyk, G. Guastalla, B. Million, E. Gregor, Oliver Wieland, F. Recchia, D. R. Napoli, A. Atac, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Science and Technology Facilities Council (UK), Swedish Research Council, Federal Ministry of Education and Research (Germany), European Commission, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Phonon, Astrophysics::High Energy Astrophysical Phenomena, Binding energy, Nuclear Theory, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 64Fe, Dipole excitation around neutron threshold, 62Fe, Subatomär fysik, 0103 physical sciences, Subatomic Physics, ddc:530, Neutron, Nuclear Physics - Experiment, Nuclear structure, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, 62 Fe, Fe, 64, 64 Fe, lcsh:QC1-999, Dipole, Fe-64, Neutron number, Fe-62, AGATA, Atomic physics, lcsh:Physics
Abstract

6 pags., 4 figs., The γ-ray emission from the nuclei Fe following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The γ decay was detected with AGATA. From the measured γ-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1 states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy., This work was partially supported by INFN (Italy) and STFC (UK), the Swedish Research Council (Vetenskapsrådet, VR 2010-147, 2011-5253, and 2016-3969), BMBF NuSTAR-AGATA 05P18RDFN9 and BMBF NuSTAR 05P18RDFN1. The project was co-funded by the European Commission under the 7th Framework Program for RTD (2007-2013) under the Capacities Program (Contract Number 262010, ENSAR). This work was par-tially supported by the Ministry of Science, and Generalitat Valenciana, Spain, under the Grants SEV-2014-0398, FPA2017-84756-C4, PROMETEO/2019/005 and by the EU FEDER funds.

Published
2020
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